▶ Watch Video: Uvalde victim’s family angered by police response

Brett Cross never imagined he’d be speaking out on behalf of a child gunned down at school. But on Wednesday, he was in Washington, D.C., where he joined families and survivors from Uvalde, Texas, and other mass shootings, to demand a ban on assault weapons. 

Cross’ nephew, 10-year-old Uziyah Garcia – who lived with him and who he considered a son – was among the 19 children killed in the Uvalde massacre.

“He was energetic, just always full of love,” Cross told CBS News. “I just want what’s best for my kids. One’s not ever going to turn 11. I have other ones that are emotionally distraught because they lost their brother.” 

The organizers of the “March Fourth” gun control rally said they want Highland Park, Illinois, where a gunman killed seven people during a 4th of July parade, to be the last community affected by a mass shooting. 

But Cross warned that every town should be prepared for a similar tragedy. 

“It’s not a matter of if it’ll happen to your kids, it’s when,” Cross said. “Because I never thought that this would happen to me.” 

President Biden signed a bipartisan gun control bill into law last month — the first in three decades. Cross said it does not go far enough. 

“We need to ban the assault rifles. I’m sure everybody has already seen video from last night,” Cross said, referring to the surveillance video which showed the Uvalde gunman arriving at Robb Elementary School and the police officers’ delayed response. “The amount of rounds that happened as quickly as they did would not have happened with another weapon.” 

“That was my son’s final moments,” Cross went on. “It’s that he walked in so nonchalantly. And then to see the police, who we tell our kids to trust and to put their faith in and everything, just stand by and do nothing. The cops there in Uvalde were cowards. It was a massacre. My son didn’t have an abdomen after this. It’s not left or right, Republican, Democratic, red or blue. Is my son’s life not worth that gun?”